Could a simple breathing exercise reduce COVID-19 deaths?
If you are unfortunate enough to be infected by COVID-19 then, for people who exhibit symptoms there is a 15%-20% chance your condition will become serious and you will need hospitalisation, a 5%-8% chance your condition will become critical and a 2.5%-4% chance you will die. However, we also know that these numbers vary significantly depending on your age, whether you have previous medical conditions and whether you are overweight. The key questions are:
- Why are these people more at risk?
- Can these people who are more at risk do anything in the short term to improve their chance of survival?
With regards to the second question, I believe that not only those people more at risk, but all of us can do things to improve our chances of a recovery.
How does coronavirus kill?
You can read a layman’s summary in this article of how coronavirus kills, but put simply, coronavirus can lead to viral pneumonia whereby “the lungs that become filled with inflammatory material are unable to get enough oxygen to the bloodstream, reducing the body’s ability to take on oxygen and get rid of carbon dioxide.” Ultimately you die of oxygen deprivation.
Why are older people more likely to become serious and critical? There are a number of contributing factors, but a major contributing factor to death in older people with pneumonia is that the fact that "lung function", our ability to breath in air and transport it into the blood stream, decreases with age.
When we are young we have plenty of excess lung function. At rest, we breathe lightly, but, even when we are doing intense physical activity, our lung function is rarely the limiting factor on the maximum amount of oxygen that we can pump around our body (a measure known as VO2 max, the Maximum Volume of Oxygen). However, as we age, our lung function decreases the point where it can indeed become the limiting factor.
For a young person with plenty of excess lung function, a reduction in the body’s ability to get oxygen into the bloodstream due to pneumonia may not be life threatening, even with a 50% reduction in function that person may still be able to get enough oxygen into the bloodstream, but for an older person with no excess lung function, such a reduction is likely to kill.
Does reduced lung function increase the risk of dying from pneumonia?
What do the research papers say to the question of whether reduced lung function increases the risk of dying from pneumonia? In this paper from 1995 titled “Risk factors for death and hospitalization from pneumonia” the authors followed 6,158 men and 7,265 women aged 30-70 years. They concluded:
“In addition to increasing age, forced expiratory volume in one second (FEV1) was strongly and consistently related to both pneumonia related mortality and hospitalization. Women with FEV1 < 60% predicted had a relative risk of 5.7 (95% confidence interval: 2.9-11) and 3.6 (2.1-6.4) for death and hospitalization, respectively, when compared with women with FEV1 > or = 100% predicted. Similar, although lower, relative risks were observed in men.”
FEV1 is the volume of air that can forcibly be blown out in the first 1 second, after taking a deep breath (please refer to the “Spirometry” page on wikipedia for a full explanation of this and other measures of lung function). In this case the authors are actually reporting on FEV1 as a percentage of FEV1%, the FEV1 predicted by taking the average FEV1 for people of the same age, sex and body composition. You can calculate your predicted values here.
The full table of their results for hospitalisation for pneumonia are in the image below. In short, women with an FEV1 that was less than 60% of that predicted were estimated to be 3.6x more likely to be hospitalised than women with an FEV1 that is equal to or greater than 100% of that predicted. For men the figure was 3.2x. For both men and women the relative risk was 1.8x when FEV1 was between 60%-79% of that predicted.
Note that being a smoker or having asthma also resulted in a much greater estimated risk.
The risk of death was comparable to that of hospitalisation, but increased to an estimated 5.7x for women with an FEV1 less than 60% of that predicted.
It is probably no surprise to you that reduced lung function does indeed increase the risk of being hospitalised for and dying from pneumonia, but this research gives solid evidence that this is indeed the case. In all there were 260 deaths with pneumonia as the main or contributory death cause, and 405 subjects had been admitted to hospital at least once because of pneumonia suggesting perhaps a 260/405 = 64% chance of death once admitted.
The research paper above looked at FEV1 as a percentage of predicted FEV1. At one level this makes sense as people of different gender and body mass may well have different requirements for oxygen usage. However, it seems less likely that your body’s requirement for oxygen decreases significantly with age. Here’s a table of predicted FEV1 in litres and how it changes by age:
Indeed, between the ages of 20 and 80 both men and women lose 38% of their FEV1 function and 29% of their FVC function (FVC is the total amount of air they can breath out in one breath).
Note that your FEV1 and FVC measures don’t decrease with age because you need less oxygen, they decrease due to “reduction in chest wall compliance and increased air trapping”. According to this paper:
"There is marked variation in the effect of aging on lung function. Aging is associated with reduction in chest wall compliance and increased air trapping. The decline in FEV1 with age likely has a nonlinear phase with acceleration in rate of decline after age 70 years. There is an increase in airspace size with aging resulting from loss of supporting tissue. Respiratory muscle strength decreases with age and much more so in men than in women. Despite these changes the respiratory system is capable of maintaining adequate oxygenation and ventilation during the entire life span. However, the respiratory system reserve is limited with age, and diminished ventilatory response to hypoxia and hypercapnia makes it more vulnerable to ventilatory failure during high demand states (ie, heart failure, pneumonia, etc) and possible poor outcomes."
If it is indeed the case that your lung function, measured by FEC or FVC, impacts your risk of being hospitalised for or dying from COVID-19 related pneumonia, then it is not surprising that this deadly virus is hitting older people harder.
Indeed, the variation in death rate from COVID-19 parallels the variation in death rate from pneumonia in general. From 2004-2012 in the UK, 1.8% of people over 80 contracted pneumonia, whereas 0.2% of people between 40-50 years old contracted pneumonia. In short people over 80 are 9x more likely to contract pneumonia than people aged 40-50.
In 2012, of the 28,952 deaths in the UK from pneumonia:
- 58 were among those aged 0–14 years of age;
- 1,374 were among those aged 15–64; and
- 27,520 were among those aged 65 and above.
How much can you improve your lung function?
Surprisingly, exercise in young, healthy people does not appear, in general, improve your lung function. Young, healthy people tend to have significant excess lung function in the first place. Exercise does, however, have a significant impact in VO2 max in young, healthy people and an 8 week exercise program can increase VO2 max by up to 20% in people who have a sedentary lifestyle and 15% in people who are moderately active. This improvement in VO2 max comes from improvements to your heart strength, capillary density and mitochondrial capacity rather than lung function.
Improving your VO2 max is a good thing to do and may help reduce your chance of hospitalisation and death from COVID-19 so get on out there and get exercising!
Exercise for older people is of course recommended too, BUT there are some simple breathing exercises that you can do whilst sitting that can have a significant impact on improving your lung function too, namely Pursed Lip Breathing and Diaphragmatic Breathing.
So what does the research say about these breathing exercises?
So far we have discussed a couple of measures of lung function, FEV1, the volume of air expelled in 1 second and VO2 max, the maximum volume of oxygen that can be pumped around the body. The next research study looked at the impact of breathing exercises on SPO2, the amount of oxygen saturation in the blood. Normal levels of SPO2 are between 95% to 99%. 90% to 94% is considered low, but may be normal for some individuals. Below 90% is considered abnormal. In patients that start to exhibit severe symptoms of COVID-19, SPO2 levels tall below 90% quite rapidly. You can use an Oximeter to measure your SPO2 levels, they cost less than ￡20 and can be bought on Amazon or eBay.
Ultimately the oxygen saturation levels in your blood are what matter. If you have good lung function your oxygen saturation levels will remain high.
This research paper studied the impact of pursed lip breathing exercises on 60 individuals split into three groups of 20. Two of the groups consisted of people with impaired lung function, people suffering from “chronic obstructive pulmonary disease” (COPD) and one group consisted of healthy individuals. The healthy group and one group with COPD carried out the “Intervention” of Pursed Lip Breathing (PLB) exercises and the other group with COPD was used as the “Control” and received routine care and drug treatment.
Before the intervention the lung function was measured by a number of standard measures. FEV1 was 1.94 and 2.02 in the two COPD groups and 3.39 in the healthy group. FEV% was 65.1% and 60.0% in the two COPD groups and 70.4% in the healthy groups. According to the earlier discussed research paper, the two COPD groups would be at significantly higher risk of hospitalisation and death from pneumonia than the healthy group.
The results showed that during the process of Pursed Lib Breathing, oxygen saturation levels increased by 2.05% and 1.70% in the COPD and healthy groups compared to a 0.75% increase in the control group which received routine treatment and drugs. After the Pursed Lip Breathing exercises were finished the increases were reduced in COPD patients, but still 1.15% and 2.85% higher in the first two groups.
Whilst these percentage improvements might seem small, the increase from 92.10% to 94.15% in the first COPD is significant in that it moved patients from below the normal range and into the normal range. For healthy patients the gains were even greater. It is also important to recognise that although the gains were greatest whilst doing the exercise, they persisted to a lesser degree post exercise.
Similar gains of 2% in SPO2 during Pursed Lip Breathing were recorded for patients with an average FEV1% of 60% in this paper.
Conclusions
My conclusion is that:
- Pursed Lib Breathing exercises have a significant impact on improving lung function as evidenced by increased SPO2 measurements.
- Improved lung function has a significant impact on reducing hospitalisation and death from pneumonia. People with higher FEV% measures have a lower risk of hospitalisation and death.
- Having a lower risk of hospitalisation and death from pneumonia will have a significant impact on reducing death rates from COVID-19
These conclusions are not a fully proven sequence, but the line of evidence suggests that the simple breathing exercise of Pursed Lip Breathing could have a significant impact on lowering the death rate from COVID-19.
Whilst Pursed Lip Breathing is a simple exercise to increase SPO2 an interesting case study of one patient may indicate that may people can significantly increase their FEV1 measure through an ongoing program of exercise. In this case a 76 year old man with COPD had an FEV1% of 42% and was admitted to hospital for pneumonia. After being treated with antibiotics and being discharged he then pursued a six month “pulmonary rehabilitation program”. The program increased his FEV1% to 62%, an incredible 50% improvement in lung function! This suggests that there is a great deal that people with lower FEV1 measures can do to increase their lung function and reduce their risk of hospitalisation and death from COVID-19.
This paper looked at the correlation between FEV1%, FEV1/FVC and SPO2 levels in order to see whether SPO2 measures, that are easy to obtain with a cheap Oximeter, are a good indicator of low FEV1% measures. They found that there was on correlation between FEV1% and SPO2 per se, but that there was a correlation between FEV1/FVC and SPO2. Their results showed that patients with an FEV1/FVC below 65% all had SPO2 levels below 94%. However the inverse was not true such that SPO2 levels below 94% were observed in patients with FEV1/FVC as high as 75%. In short, FEV1/FVC is a reasonably good predictor of SPO2, but SPO2 is not a good predictor of FEV1/FVC.
It’s useful to look at why Pursed Lib Breathing may be effective. As one paper describes it:
Pursed-lip breathing is believed to increase positive pressure generated within the airways and to buttress or stent the small bronchioles, thereby preventing premature airway collapse. This stenting of the airways, which should promote effective expiration, potentially results in a reduced functional residual capacity. This breathing pattern significantly decreases the respiratory rate and increases the tidal volume, resulting in improved alveolar ventilation (measured by arterial partial pressure of carbon dioxide [Po2]) and enhanced ventilation of previously underventilated areas.
In other words, it may have a similar effect to Continuous Positive Airway Pressure (CPAP) ventilators like the new ones designed by the F1 teams.
It's also interesting to revisit the question of why young, healthy people have excess lung function in the first place, especially since the other factors that influence your VO2 max seem to be in perfect balance with exercise improving all in equal amounts, a concept known "symmorphosis". My guess is that it was an evolutionary development specifically to help people survive respiratory diseases. In ages gone by young people without excess lung capacity simply did not survive.
Pursed Lip Breathing to improve your lung function is of course only one part of the answer to increasing your chances of surviving Coronavirus, there are many other positive things you can do to improve your immune system, lung function and general health. This is one of the more comprehensive articles related to helping people suffering from COPD, but its recommendations are likely just as applicable for helping people prevent hospitalisation and death from COVID-19:
For more advice on Pursed Lip Breathing, Diaphragmic Breathing and other exercises to improve your lung function, check out these articles and videos from the American Lung Foundation: